A number of publications describe the production of filled food products. Many describe machinery employed for the production of the dual textures, which is generally accomplished by coextrusion or by formation of the shell or casing followed by filling. Many others describe special formulations to keep the filling from migrating and the product from getting soggy.
U.S. Pat. No. 3,492,127 to Ketch and Barton, for example, suggested that the filling of a filled pastry be dehydrated to an overall moisture content of less than 6%, more commonly less than 4%, and preferably less than about 2%, and then rehydrated prior to baking. Cheese such as cottage cheese and other types in a dessicated form were disclosed as possible fillers, but the patent was chiefly directed to the preparation of shelf-stable pies filled with freeze-dried, vacuum-dried or air-dried fruit pieces. Rehydration was accomplished by adding an aqueous fluid through the upper crust. The method was, therefore, chiefly useful for large products contained in a dish or pie plate, rather than for snacks.
In U.S. Pat. No. 4,612,198, Wallin, et al., disclosed a filled pastry that contained a fairly high moisture filling yet retained structural integrity on toasting. The pastry was formulated by carefully controlling filling and casing viscosity and pH, and preparing a laminated dough pad that was stable at the filling interface. The pH and viscosity ranges were critical, which complicated the process. Also the patent was directed to the production of toaster breakfast pastries such as those filled with fruit or jellies which have product instability primarily caused by acid and water migration from the filling into the dough, limiting the applicability of the invention to other product types.
Both Ward, et al., U.S. Pat. No. 4,613,509, and Wainwright, U.S. Pat. No. 4,618,499, disclosed slitted center-filled food products. The former patent disclosed a process for producing center-filled food products by forming a hollow cylindrical edible shell having a single continuous longitudinal slit, through which was inserted a filling that had to be substantially stationary at product storage temperatures. The latter disclosed the cooking and extrusion of a casing, which was then slit open for filling insertion. The processes were suggested to avoid various problems encountered in filling brittle shells or in coextruding product components that exhibit very different heating and cooling characteristics, but the slits left in the finished products would provide vents that could leak if the final products were heated.
In U.S. Pat. No. 4,661,360, Smith disclosed peanut butter-filled snack products formed by coating the filling with a hydrophilic material and then surrounding the coated filling with a layer of dough. The snack was baked after the layers were applied to the filling, but the patent did not report about product performance on reheating.
Barry, et al., in U.S. Pat. No. 4,919,947, disclosed fillings that were formulated to control the crystal structure of the shortening and the particle size of the flavoring so they could be pumped into outer shells of cooked dough without clogging the nozzle. The patent addressed the structuring of fillings so that they were pumpable prior to final formulation of the product, and not the reheating of filled products.
It would be desirable to have a formulation specifically directed to a savory cheese-filled snack that can be baked or microwaved.